A luminous display instrument conventionally includes a light source which, in order to function, has to be connected to the vehicle battery. A printed circuit board, on which the light source is mounted, is to be generally invisible to the vehicle occupants and is therefore separated from the passenger cell by a trim element. The trim element includes a window, which is necessary in order to allow the light of the light source through, but is otherwise light impermeable. On the one hand, the window should be relative small so that the light source is visible in it at most when it is switched on. However, the smaller the window, the more exact it has to be positioned relative to the light source so that it is caught by the light of the light source. When trim element and luminous display instrument are fastened on a same support structure of the vehicle independently of one another, the contacting of the luminous display instrument is simple, since it can take place before the attachment of the trim element. However, tolerances in the positioning can result in that the light of the light source does not exactly catch the window and is therefore hard to see. More exact positioning is possible when the luminous display instrument is first fastened to the trim element and the trim element to the support structure thereafter, but the trim element then interferes with the contacting since the dimensions as a rule are larger than those of the luminous display instrument or the printed circuit board carrying it.
There is therefore a need for a design which can be mounted quickly and efficiently and in the process ensures both simple contacting of the luminous display instrument and also good visibility.